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Lichens may be long-lived, with some considered to be among the oldest living things. They are among the first living things to grow on fresh rock exposed after an event such as a landslide. | Lichens may be long-lived, with some considered to be among the oldest living things. They are among the first living things to grow on fresh rock exposed after an event such as a landslide. | ||
==Lichens in Antarctica== | |||
Three main types of lichens exist in [[Antarctica]]: | |||
:* Crustose lichens, which form a thin crust on the surface of the substrate they grow on. | |||
:* Foliose lichens, which form leaf like lobes. | |||
:* Fruticose lichens which have a shrubby growth habit. | |||
Lichens have very slow rates of growth. In the most favorable of conditions in the northernmost areas of coastal Antarctica, growth rates reach 1 cm or more per 100 years. In the harsher environment of mainland [[Westarctica]], growth is much slower, and may be as little as 1 cm per 1000 years for ''Buellia frigida''. | |||
Lichens can be found growing in most areas of the Antarctic capable of supporting plant life. Currently four general distributional patterns of lichens are known. These are: species confined to the Maritime Antarctic; those found in the Peninsula and extending to the Lesser Antarctic; those with a Circum Antarctic distribution; and those with very disrupted or Disjunct distribution patterns. | |||
The Maritime Antarctic lichens are restricted to the northern Peninsula and nearby islands. Many of the lichens found in Antarctica are restricted to this area. A number of the lichen species found here are also found in the subantarctic islands and the colder parts of the southern continents, and may represent a southern extension of these populations. This area has the greatest species diversity in Antarctica. | |||
Lichens have been collected from as far south as 86°30'. | |||
===Adaptations to Antarctica=== | |||
Lichens have a number of adaptations that enable them to survive in Antarctica. They are able to exhibit net photosynthesis while frozen at temperatures as low as -20°C. They can absorb water from a saturated atmosphere when covered by snow. Additionally, snow cover affords protection from the elements and most growth appears to occur when they are buried beneath at least a thin protective layer of snow. | |||
They can survive long unfavorable periods of drought in a dry and inactive state. In continental Antarctica, many lichens are able to absorb water vapor from snow and ice. | |||
==Effect of climate change on Antarctic lichen== | |||
According to a 2017 study published by Swedish University of Agricultural Sciences, short periods of increased temperature can push Antarctic lichens to their physiological limits, potentially threatening their survival. The observed effect is significant enough to lead the study group to conclude that a continued increase in temperature will lead to a severe species loss among Antarctic vegetation. | |||
Lichen species native to southern latitudes appeared unable to adapt to rising temperature and were more likely to die out as opposed to lichen species which were native to northern latitudes, but had colonized Antarctic habitats. Those lichen were more readily adaptable to rising temperature. | |||
==Human use== | ==Human use== | ||
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===As an alcoholic drink=== | ===As an alcoholic drink=== | ||
==External Links== | |||
[https://www.slu.se/en/ew-news/2017/11/antarctic-lichens/ SLU study on sichens] | |||
[http://www.antarctica.gov.au/about-antarctica/wildlife/plants/lichens/ Australian Antarctic Division article on lichen] | |||
[[Category:Science]] | [[Category:Science]] | ||
[[Category:Plants of Westarctica]] | [[Category:Plants of Westarctica]] | ||